The present invention concerns a sealing ring assembly for increasing the effectiveness of deformable O-rings and other deformable type seals for use as a sliding seal member, as for example a seal member on a piston or rod or as a stationary seal member, as for example a seal member on a well tubing to form a seal between that tubing and a larger concentric casing.
Deformable seal materials currently used as sliding fluid seals or stationary seals tend to extrude under high pressure, for example, 10,000 to 20,000 psi and high temperatures, e.g., 300.degree. to 500.degree. F. and will function properly only if the gap width (the space between the concentric cylindrical members) such materials must bridge is less than several thousandths of an inch. The seal material extrudes through any larger bridging gap width and may cause significant problems, as for example, in maintaining the seal and/or hindering or preventing removal of the retaining ring from its seal position and/or fouling of the cylindrical member and retaining ring associated with it. Fabrication tolerances, galling and parts assembly problems set practical limits on the dimensions of the retaining ring and seal material. Such limits do not permit a gap between the cylindrical members small enough to prevent extrusion of the seal material. The present invention uses a gap closing, radially expansible-contractible non-deformable split ring, having a portion or all of one of its surfaces tapered, to close that gap to about zero. Use of this ring prevents extrusion of the seal material while permitting practical fabrication tolerances for the assembly of the equipment and operation of the retaining ring.